In this article, we’re going to discuss how much a gallon of milk weighs and what factors can affect its weight. Read on to learn more.

How Much Does a Gallon of Milk Weigh

A gallon of whole milk weighs 8.6 pounds. The weight of a quart of milk is 2.15 lbs.

Weight is a measurement of mass times acceleration, in this case, mass times the acceleration of gravity.

We know the acceleration of gravity is 9.8 meters per second squared. So, now we need to know the mass of the milk.

Mass is equal to volume times density. The volume of a gallon of milk actually depends on where you purchase your milk.

In the US, the volume is 3.785 liters or 231 cubic inches. In the UK, an imperial gallon of milk is 4.546 liters or 277.4 cubic inches.

Now we need to find the density of milk.

The Density of Milk

Eighty-seven percent of a gallon of milk is water. Condensed milk and evaporated milk contain less water, or you can purchase powdered dry milk.

Each of these options will have a different density, and thus a different weight.

Another factor that influences the density of milk is the fat content. Above, we discussed whole milk. However, skim, 1%, or 2% milk will have slightly different densities, thus slightly different weights.

On average, the density of milk lies between 1.026 g/cm3 and 1.034 g/cm3 at 20°C.

Temperature and the Weight of Milk

Notice we said “at 20°C” above. The density of milk, as with any substance, also varies depending on temperature.

For example, when milk is frozen, the water content expands. This decreases the density, and therefore also decreases the weight.

Final Calculations

Assuming room temperature, the weight of a gallon of milk is found first by multiplying the volume by the density, then multiplying that number by 9.8 meters per second squared.

So, a US gallon of milk weighs 8.6 pounds, while a UK gallon of milk weighs 10.32 pounds.

Transportation Considerations

Milk powder made from a gallon of US milk weighs around one pound. In comparison to fresh milk, milk powder allows you to transport a much larger volume of milk.

In terms of transportation expenses, this means that you can carry eight to ten times as much milk as a powdered form.

Importance of Weight of Milk in Cooking or Baking

Recipes typically use volume rather than weight to calculate the amount of milk to use. This is because weighing a liquid is far more difficult than measuring its volume.

A weight scale is required if you wish to weigh your milk for a recipe.

Takeaway

In general, an eight-pound gallon of milk is the average weight in the US. That said, a typical eight-pound container of milk might vary in weight depending on the type of milk you consume.